An organic photoconductor (OPC) is one of the components in an electrophotographic (EP) printer. A latent image, which is a surface charge pattern, is created on the OPC prior to contact with a development system containing charged marking particles. This is accomplished by uniformly charging the OPC surface, followed by selective illumination that locally generates opposite charges within the bulk of the OPC which then move to the surface and locally neutralize deposited charges. The OPC frequently has two layers: an inner layer for generating charges (charge generation layer—CGL) and an outer layer containing molecular moieties for facilitating charge movement (charge transport layer—CTL). The OPC element must have very uniform and defect-free structural and electrical characteristics. Its usable lifetime is often determined by the occurrence of physical defects introduced by mechanical, physicochemical and electrical interactions between the surface of the CTL and one or more elements of the electrophotographic process (commonly known as “OPC wear-out”). Some of the proposed solutions addressing this issue involve coating the CTL surface with a hard, inorganic film that may significantly raise the OPC cost and introduce other deleterious effects associated with the contamination particles originating from the inorganic coating.
Alternative solutions have proposed coating the OPC with an organic coating having superior damage resistance and electrical properties corresponding to the original OPC. This might be accomplished by using a mixture of damage-resistant polymer (matrix) and molecular moieties (CTM—charge transport material) providing electrical charge conduction, and coating the original OPC with their solvent-based mixture. This solution has not been successful due to a lack of appropriate hole-conducting dopants that can be used with a solvent that does not attack the original OPC. All commonly-available hole-CTMs require solvents that are incompatible with polycarbonate, the matrix component for most of the commercial OPCs.